The microphones adopted in recent years use capacitive transducers manufactured via micro electro-mechanical systems (MEMS) technology (hereinafter also called MEMS microphones). A capacitive transducer has a vibrating electrode membrane that vibrates under pressure; the vibrating electrode membrane faces a backplate to which the electrode membrane is secured with an air gap. The backplate has a plurality of through-holes. Japanese Patent Document No. 4338395 proposes an acoustic transducer with a cover part, a substrate attached to the cover part, and a diaphragm placed between the cover part and the substrate. The flat surface of the cover part includes a plurality of perforations.